The invention is generally related to providing automatic exposure correction in electronic imaging systems. The invention is related more specifically to a method and apparatus for extending the dynamic exposure range of electronic imaging systems that utilize electronic image sensor devices to generate image data.
Electronic image sensor devices have been utilized in a wide variety of products including film scanners, motion video cameras and still video cameras, to generate image data. The analog image output signal from the electronic image sensor is typically converted to a digital image signal by an analog-to-digital converter prior to image processing or storage. It has been found that most scenes have a natural scene contrast of about a ten bit dynamic range, thereby requiring the use of standard sixteen bit devices, at a minimum, to perform the digital conversion and signal processing. The expense of electronic imaging systems could be reduced if lower cost eight bit devices could be used to convert and process the image signal.